Allomaieta isauroi J.S.Murillo, Humberto Mend., Edwin Trujillo & O.Perdomo, 2025

Murillo-Serna, Jhon S., Trujillo-Trujillo, Edwin, David-Higuita, Heriberto A., Perdomo, Oscar & Mendoza-Cifuentes, Humberto, 2025, Allomaieta isauroi (Melastomataceae, Cyphostyleae): a new species from the Andean-Amazonian Foothills of Colombia, Phytotaxa 711 (1), pp. 81-88 : 82-86

publication ID	https://doi.org/10.11646/phytotaxa.711.1.6
DOI	https://doi.org/10.5281/zenodo.16713306
persistent identifier	https://treatment.plazi.org/id/03A287D9-FFCB-C001-FF15-DCD83BBF9111
treatment provided by	Felipe
scientific name	Allomaieta isauroi J.S.Murillo, Humberto Mend., Edwin Trujillo & O.Perdomo
status	sp. nov.

Treatment

Allomaieta isauroi J.S.Murillo, Humberto Mend., Edwin Trujillo & O.Perdomo , sp. nov. ( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Type:— COLOMBIA. Caquetá: Municipio de Florencia, Vereda El Caraño, Finca Las Brisas, propiedad de Isauro Trujillo. Bosque al lado del salto del Caraño, 1°44’08’’ N, - 75°40’39’’ W, 922 m, 21 February 2020 (fl & fr), O. Perdomo & I. Trujillo 152 (holotype: HUA-230209!).

Diagnosis:— Allomaieta isauroi is characterized by the combination of leaf blades with one pair of suprabasal veins, plus an additional marginal pair, turbinate flower buds, petals light pink, basally white, and apically obtuse anthers. This species is morphologically similar to Allomaieta javierbarrigae but differs in the secondary pair of leaf blade 0.6– 10.9 mm above the base (vs. basal venation or 3–4 mm above the base in A. javierbarrigae ), hypanthium covered with hispid indumentum and flattened trichomes up to 1.5 mm long (vs. lax indument with trichomes 0.2–0.7 mm long), obconical hypanthium (vs. broadly campanulate), and petals larger than 2.5 cm long (vs. smaller than 2 cm long).

Shrub 1.5–3.5 m tall. Stems and petioles covered by hispid indument of slightly roughened trichomes 0.5–1 mm long. Internodes 0.8–7.9 cm long, 0.9–2.7 mm diameter, terete; nodes swollen. Leaves opposite, slightly unequal at the same node; petioles terete, 5–35.9 mm long, 0.5–1.3 mm diameter; leaf blades papyraceous, 4.2–20 × 1.6–6.9 cm, lanceolate, elliptic or lanceolate-elliptic, base obtuse, apex attenuate slightly falcate, margin dentate with trichomes 0.5–1.2 mm long; venation acrodromous, with one pair of suprabasal, secondary veins plus an additional marginal pair, the innermost pair alternate (rarely opposite), joining the primary vein 0.6–10.9 mm above the base, 14–37 tertiary (transversals) adjacent to the primary vein (inside the innermost pair), 1–10.9 mm apart; primary to quaternary veins raised on the abaxial surface and impressed in the adaxial surface; the abaxial surface with primary and secondary veins covered by hispid trichomes 0.5–0.7 mm long, tertiary veins and surface pubescent with thin trichomes of 0.2–1 mm long; indument on adaxial surface covered by bulla-based trichomes without enations ca. 0.2 mm long, hispid, ca. 0.5 mm long on the primary vein. Inflorescences 2.5–5.8 cm long, axillary or terminal, cymes with 1–2 pairs of monochasial or dichasial paracladia (flowers rarely solitary), with the same indumentum as the petioles; peduncle 7.2–37.8 mm long, rachis with 1–2 internodes, first internode 6.6–21.6 mm long, first paracladia 3.7–20 mm long, (1–)7–9 flowers per inflorescence; proximal bracts 6–7 × 1.5 mm, sessile, linear; bracteoles 3 per each flower 6–7.3 × 0.6–1.3 mm, sessile, linear, covered by hispid trichomes, deciduous during anthesis. Flower buds turbinate. Flowers (4–)5–merous, haplostemonous, pedicel ca. 1.5 mm long. Hypanthium ca. 6 mm long up to the torus, ca. 5 mm diameter in the torus, obconical, covered by hispid indumentum, and trichomes flattened, reddish, up to 1.5 mm long. Calyx calyptrate, calyptra in flower buds ca. 10 mm long, ca. 7 mm diameter in base, opening by (4–)5 regular triangularvalves, deciduous in anthesis, indument externally such as the hypanthium, internally glabrous; relictual tube ca. 0.5 mm long. Petals at anthesis pink and basally white, 25.9–27.4 × 24.4–26.1 mm, obtriangular, apex truncate, margin entire, glabrous. Stamens isomorphic, isometric, (4–)5 antesepalous, surrounding by one flank the style causing a slight zygomorphicy; filaments 3.5–4.7 mm long., 0.3–0.5 mm diameter, white; anthers 4.3–4.7 mm long., 0.9–1.1 mm diameter, oblong, apically obtuse, yellow, pore located in a ventral canal ca. 0.4 mm from the apex and ca. 0.3 mm wide, pedoconnective absent, connective not extended below thecae but swollen 0.5–0.7 mm long. 0.7–0.8 mm wide. Ovary 5-celled in 5-merous flowers (not observed in 4-merous ones), totally inferior, the apex glabrous, 2.8–3 mm long., 2.1–2.5 mm diameter in longitudinal section, hypanthium diameter in the middle of the locules 3.2–4 mm. Style nutant, 5.4–5.7 mm long, base 0.3–0.4 mm diameter, glabrous; stigma 0.8–0.9 mm diameter, papillose. Capsule pale green with reddish trichomes when immature, totally brown when maturing, 7.3–8.3 mm long, 5.6–6.6 mm diameter, subspherical to cupuliform; pedicel 2.3–4.2 mm long. Seeds 0.5–0.6 mm long., ca. 0.3 mm diameter, cuneiform.

Additional specimen examined (paratype):— COLOMBIA. Caquetá. Mun. Florencia, vereda El Caraño, finca Las Brisas, propiedad de Isauro Trujillo. Bosque al lado del salto del Caraño, 954 m, 1°44’08’’N,- 75°40’39’’W, 03 July 2020 (fl. & fr.), E. Trujillo-T., W. Trujillo-C., O. Perdomo, A. Lizcano & I. Trujillo 7226 (HUA-230210!).

Etymology:— The epithet honors Isauro Trujillo, in recognition of his commitment to the care and defense of the Amazon foothills forests. The new Allomaieta species named in his honor grows within the grounds of his privately managed nature reserve.

Distribution, ecology, and phenology:— Allomaieta isauroi is known only from its type locality in the eastern slope of the Eastern cordillera of the Colombian Andes, at an elevation close to 950 m ( Fig. 3 View FIGURE 3 ). It grows in the understory of riparian forests, in wet forests of the Amazonian foothills. All known specimens have been collected with flowers, flower buds, and fruits in February and July.

Conservation status:— Allomaieta isauroi is known only from two collections from a single location near the city of Florencia (Department of Caqueta), with an Area of Occupancy (AOO) of less than 10 km ² and only a small number of individuals growing in an unprotected area. Furthermore, due to urban and agricultural expansion ( Fig. 3 View FIGURE 3 ), and the restriction of its habitat to ombrophilous environments, this species is at risk of extinction, and its categorization as “Critically Endangered” (CR) B2ab(ii, iii,v) is proposed, following the IUCN categories and criteria ( IUCN, 2012).

Notes:— Allomaieta isauroi is the second species of the genus known from the Andean-Amazonian foothills of Colombia (on the eastern slopes of the Andes). It can be confused with A. caucana Lozano in Lozano & Becerra-de-Lozano (1999: 11) and A. villosa ( Gleason 1929: 100) Lozano in Lozano & Becerra-de-Lozano (1999: 11), due to the type of indument, the contour of the leaf blade, the size of the flower buds, and the color of the petals. The inflorescences in A. isauroi are shorter and its leaf blades have a pair of secondaries (not including the marginal pair). In contrast, in the other two species, the inflorescences are longer, and the leaf blades have two pairs of secondaries (not including the marginal pair). In relation to distribution, A. caucana is distributed along the western slope of the Western Cordillera, while A. villosa occurs in the inter-Andean valleys of the Central Cordillera of Colombia.

Allomaieta isauroi grows on the eastern slope of the Eastern Cordillera, as does A. javierbarrigae Mendoza-Cifuentes (2018: 11) View in CoL ; however, these species have never been observed growing together. See diagnosis and Table 1 for a complete set of distinguishing characteristics between these species.